gods-eye-view/src/layers/weather/infraredImage.test.mjs

import test from 'node:test';
import assert from 'node:assert/strict';
import {
  acquireInfraredMosaic,
  acquireWeatherImage,
  decodeInfraredImage,
  processInfraredImage,
  MAX_MOSAIC_BYTES,
} from './infraredImage.js';

function canvas() {
  const output = {};
  output.getContext = () => ({
    setTransform: (...matrix) => {
      output.transforms = [...(output.transforms ?? []), matrix];
    },
    drawImage: (image) => {
      output.image = image;
      output.drawnWith = output.transforms?.at(-1) ?? null;
    },
    getImageData: () => ({ data: new Uint8ClampedArray([194, 0, 0, 200]) }),
    putImageData: (pixels) => {
      output.pixels = pixels.data;
    },
  });
  return output;
}

test('the transfer is applied to the canvas pixels in place, with no copy written back', () => {
  let read = null;
  const output = {};
  output.getContext = () => ({
    drawImage() {},
    getImageData: () => {
      read = { data: new Uint8ClampedArray([194, 0, 0, 200]) };
      // A second full-size buffer copied over the first is what this guards.
      read.data.set = () => {
        throw new Error('the canvas pixels were overwritten from a copy');
      };
      return read;
    },
    putImageData: (pixels) => {
      output.pixels = pixels;
    },
  });
  processInfraredImage({ width: 1, height: 1 }, 'filtered', () => output);
  assert.equal(output.pixels, read);
  assert.deepEqual([...read.data], [194, 0, 0, 98]);
});

test('decoded pixels are processed once on a same-sized canvas', () => {
  const image = { width: 1, height: 1 };
  const output = processInfraredImage(image, 'filtered', canvas);
  assert.equal(output.width, 1);
  assert.equal(output.height, 1);
  assert.equal(output.image, image);
  assert.deepEqual([...output.pixels], [194, 0, 0, 98]);
  assert.deepEqual(
    [...processInfraredImage(image, 50, canvas).pixels],
    [194, 0, 0, 149],
    'half-strength filter retains a midpoint haze',
  );
  assert.deepEqual(
    [...processInfraredImage(image, 0, canvas).pixels],
    [194, 0, 0, 200],
  );
  assert.deepEqual(
    [...processInfraredImage(image, 'full', canvas).pixels],
    [194, 0, 0, 200],
  );
});

test('flipY draws a bottom-up image upright, then restores the transform', () => {
  const image = { width: 4, height: 8 };
  assert.equal(processInfraredImage(image, 'full', canvas).drawnWith, null);
  const output = processInfraredImage(image, 'full', canvas, { flipY: true });
  assert.deepEqual(output.drawnWith, [1, 0, 0, -1, 0, 8]);
  assert.deepEqual(output.transforms.at(-1), [1, 0, 0, 1, 0, 0]);
});

test('mosaic fetch is capped at 4 MiB, forwards cancellation, and releases decoded images', async () => {
  const controller = new AbortController();
  let closes = 0,
    fetches = 0,
    clock = 10,
    fetched = false;
  const options = {
    signal: controller.signal,
    mode: 'filtered',
    createCanvas: canvas,
    now: () => clock,
    onFetched: () => {
      fetched = true;
    },
    fetchImpl: async (url, { signal }) => {
      fetches++;
      assert.match(url, /^\/api\/weather\/image\?product=clouds&time=/);
      assert.equal(signal, controller.signal);
      return new Response(new Uint8Array([1, 2, 3]));
    },
    decodeImage: async (blob) => {
      assert.equal(fetched, true);
      assert.equal(blob.size, 3);
      assert.equal(blob.type, 'image/png');
      clock = 25;
      return {
        width: 2048,
        height: 1024,
        close() {
          closes++;
        },
      };
    },
  };
  const result = await acquireInfraredMosaic(
    '2026-09-15T20:00:00.000Z',
    options,
  );
  assert.equal(fetches, 1);
  assert.equal(closes, 1);
  assert.equal(result.decodeMs, 15);
  assert.equal(result.texture.width, 2048);
  for (const response of [
    new Response('', {
      headers: { 'content-length': String(MAX_MOSAIC_BYTES + 1) },
    }),
    new Response(new Uint8Array(MAX_MOSAIC_BYTES + 1)),
  ]) {
    await assert.rejects(
      acquireInfraredMosaic('2026-09-15', {
        ...options,
        fetchImpl: async () => response,
        decodeImage: () => assert.fail('oversized image must not decode'),
      }),
      { code: 'RESPONSE_TOO_LARGE' },
    );
  }
  await assert.rejects(
    acquireInfraredMosaic('2026-09-15', {
      ...options,
      decodeImage: async () => {
        controller.abort();
        return {
          width: 2048,
          height: 1024,
          close() {
            closes++;
          },
        };
      },
    }),
    { name: 'AbortError' },
  );
  assert.equal(closes, 2);
});

test('bitmap decoding and Image fallback release resources on success, error and abort', async (t) => {
  const original = Object.getOwnPropertyDescriptor(
    globalThis,
    'createImageBitmap',
  );
  t.after(() => {
    if (original)
      Object.defineProperty(globalThis, 'createImageBitmap', original);
    else delete globalThis.createImageBitmap;
  });
  const bitmap = {};
  globalThis.createImageBitmap = async () => bitmap;
  assert.equal(
    await decodeInfraredImage(new Blob(), new AbortController().signal),
    bitmap,
  );
  globalThis.createImageBitmap = undefined;
  const images = [],
    revoked = [];
  const originalImage = globalThis.Image;
  globalThis.Image = class {
    constructor() {
      images.push(this);
    }
  };
  t.after(() => {
    if (originalImage) globalThis.Image = originalImage;
    else delete globalThis.Image;
  });
  t.mock.method(URL, 'createObjectURL', () => 'blob:test');
  t.mock.method(URL, 'revokeObjectURL', (url) => revoked.push(url));
  for (const action of ['load', 'error', 'abort']) {
    const controller = new AbortController();
    const pending = decodeInfraredImage(new Blob(), controller.signal);
    const image = images.at(-1);
    assert.equal(image.src, 'blob:test');
    if (action === 'load') {
      image.onload();
      assert.equal(await pending, image);
    } else if (action === 'error') {
      image.onerror();
      await assert.rejects(pending, /decode failed/);
    } else {
      controller.abort();
      await assert.rejects(pending, { name: 'AbortError' });
      assert.equal(image.src, '');
    }
    assert.equal(image.onload, null);
    assert.equal(image.onerror, null);
  }
  assert.deepEqual(revoked, ['blob:test', 'blob:test', 'blob:test']);
});

const pixels = (width, height) => ({
  width,
  height,
  closes: 0,
  close() {
    this.closes++;
  },
});

test('a frame source supplies the image: nothing is fetched or decoded and the pixels are released', async () => {
  const controller = new AbortController();
  const requests = [];
  const bitmap = pixels(2048, 1024);
  let clock = 5,
    fetched = false;
  const result = await acquireInfraredMosaic('2026-09-15T20:00:00.000Z', {
    signal: controller.signal,
    mode: 'filtered',
    createCanvas: canvas,
    now: () => clock,
    onFetched: () => {
      fetched = true;
    },
    fetchImpl: () => assert.fail('a supplied frame is not fetched'),
    decodeImage: () => assert.fail('a supplied frame is not decoded'),
    frameSource: {
      getImage: async (request) => {
        requests.push(request);
        clock = 12;
        return bitmap;
      },
    },
  });
  assert.deepEqual(requests, [
    {
      product: 'clouds',
      time: '2026-09-15T20:00:00.000Z',
      size: { width: 2048, height: 1024 },
      bbox: null,
      signal: controller.signal,
    },
  ]);
  assert.equal(fetched, true);
  assert.equal(result.decodeMs, 7);
  assert.equal(result.texture.width, 2048);
  assert.equal(result.texture.height, 1024);
  assert.equal(result.texture.image, bitmap);
  assert.deepEqual(
    [...result.texture.pixels],
    [194, 0, 0, 98],
    'infrared frames get the display transfer',
  );
  assert.equal(bitmap.closes, 1);
});

test('supplied detail windows carry their bbox; ImageData is put, radar keeps its pixels', async (t) => {
  const had = Object.hasOwn(globalThis, 'ImageData');
  const previous = globalThis.ImageData;
  globalThis.ImageData = class ImageData {
    width = 4096;
    height = 2048;
    data = new Uint8ClampedArray([1, 2, 3, 4]);
  };
  t.after(() => {
    if (had) globalThis.ImageData = previous;
    else delete globalThis.ImageData;
  });
  const data = new globalThis.ImageData();
  const bbox = { west: -102, south: 34, east: -96, north: 37 };
  let request;
  const { texture } = await acquireWeatherImage('radar', 't', {
    signal: new AbortController().signal,
    size: { width: 4096, height: 2048 },
    bbox,
    createCanvas: canvas,
    fetchImpl: () => assert.fail('no fetch'),
    frameSource: {
      getImage: async (value) => {
        request = value;
        return data;
      },
    },
  });
  assert.equal(request.bbox, bbox);
  assert.equal(
    texture.pixels,
    data.data,
    'ImageData is put as it is; radar has no transfer',
  );
  assert.equal(texture.image, undefined, 'ImageData is not drawn as an image');
  assert.equal(texture.width, 4096);
});

test('a supplied frame of the wrong size is refused and still released', async () => {
  const wrong = pixels(1024, 512);
  await assert.rejects(
    acquireInfraredMosaic('t', {
      signal: new AbortController().signal,
      mode: 'filtered',
      createCanvas: canvas,
      frameSource: { getImage: async () => wrong },
    }),
    /Invalid weather image dimensions/,
  );
  assert.equal(wrong.closes, 1);
  await assert.rejects(
    acquireInfraredMosaic('t', {
      signal: new AbortController().signal,
      mode: 'filtered',
      createCanvas: canvas,
      frameSource: { getImage: async () => undefined },
    }),
    /Invalid weather image dimensions/,
  );
});

test('cancellation reaches the frame source, and a frame that arrives after it is released', async () => {
  const controller = new AbortController();
  const late = pixels(2048, 1024);
  let seen;
  const pending = acquireInfraredMosaic('t', {
    signal: controller.signal,
    mode: 'filtered',
    createCanvas: () => assert.fail('a cancelled frame is not drawn'),
    frameSource: {
      getImage: async ({ signal }) => {
        seen = signal;
        await flushMicrotasks();
        return late;
      },
    },
  });
  controller.abort();
  await assert.rejects(pending, { name: 'AbortError' });
  assert.equal(seen, controller.signal);
  assert.equal(late.closes, 1);
  const aborted = new AbortController();
  aborted.abort();
  await assert.rejects(
    acquireInfraredMosaic('t', {
      signal: aborted.signal,
      frameSource: { getImage: () => assert.fail('already cancelled') },
    }),
    { name: 'AbortError' },
  );
});

async function flushMicrotasks() {
  for (let i = 0; i < 5; i++) await Promise.resolve();
}